A conventional screw driver generally includes a handle and a shank has one end fixed to the handle and the other end of the shank has a function end which is engaged with an object such as a nut or a screw. The user holds and rotates the handle and the shank is rotated to loosen or tighten the object. The handle has a diameter that is larger than a diameter of the shank so that when rotating the handle, the shank is rotated to apply a large torque to loosen or tighten the object. It is noted that during loosening the object, only the beginning step requires a larger torque, once the object is loosened, the object can be easily rotated with smaller torque. However, the user cannot quickly rotate the screw driver by rotating the handle. In other words, the conventional screw tool does not have a function that is needed to quickly rotate the object.
The present invention intends to provide a hand tool that includes a clutch device in the handle and the shank is engaged with the clutch device when a large torque is needed to be applied to the object, and when the clutch device releases the shank, the shank can be quickly rotated independently with small torque.